Add rename namespace command

docs/manipulating_code/refactoring.md

@@ -4,21 +4,29 @@ Sometimes you want to make big changes to your codebase like moving methods or c
 
 Psalm has a refactoring tool you can access with either `vendor/bin/psalm-refactor` or `vendor/bin/psalm --refactor`, followed by appropriate commands.
 
+## Moving all classes from one namespace to another
+
+```
+vendor/bin/psalm-refactor --move "Ns1\*" --into "Some\Other\Namespace"
+```
+
+This moves all classes in `Ns1` (e.g. `Ns1\Foo`, `Ns1\Baz`) into the specified namespace. Files are moved as necessary.
+
 ## Moving classes between namespaces
 
 ```
 vendor/bin/psalm-refactor --move "Ns1\Foo" --into "Ns2"
 ```
 
-This tells Psalm to move class `Ns1\Foo` into the namespace `Ns2`, so any reference to `Ns1\Foo` becomes `Ns2\Foo`).
+This tells Psalm to move class `Ns1\Foo` into the namespace `Ns2`, so any reference to `Ns1\Foo` becomes `Ns2\Foo`). Files are moved as necessary.
 
 ## Moving and renaming classes
 
 ```
 vendor/bin/psalm-refactor --rename "Ns1\Foo" --to "Ns2\Bar\Baz"
 ```
 
-This tells Psalm to move class `Ns1\Foo` into the namespace `Ns2\Bar` and rename it to `Baz`, so any reference to `Ns1\Foo` becomes `Ns2\Bar\Baz`).
+This tells Psalm to move class `Ns1\Foo` into the namespace `Ns2\Bar` and rename it to `Baz`, so any reference to `Ns1\Foo` becomes `Ns2\Bar\Baz`). Files are moved as necessary.
 
 ## Moving methods between classes